Twyer construction for furnaces and underfeed stokers



H. SCHMIDT.

TWYER CONSTRUCTION FOR FURNACES AND UNDERFEED STOKEHSl .Lsmma APPLICATION FILED AUG-31,1918.

Patented'June 7, 1921.

2 SHEETS-SHEET I.

v Inventor;

.-.F%wwMSch/m# Attys.

' H. SCHMIDT.

TWYER CONSTRUCTION FOR FURNACES AND UNDERFEED STOK ERS.

APPLICATION FILED AUG-31,1918.

1,380,844. 4 Patented June 7, 1921.

2 SHEETS-SHEET 2.

v area are rat eer e-s.

HERMAN scmanrr, or 1TEw YORK, N. Y., ASSIGNOR TO ERNEST B. PRIEBE-Aim WARREN c. DRAKE, BOTH OF mwoon, NEW YORK. v

TW'YER QONSTRUCTION FOR FURNACES AND UNDERFEED STO KERS To all whom it may concern at the bridge wall.

Be it known that I: HERMAN SCHMIDT, a

citizen of the United States, residing at New York, in the countyof New York and State of New York, have invented certain new and useful Improvements in Twyer Construction for Furnaces and. Underfeed Stokers, of which the'following is a specification.

This invention is a novel twyer construction for automatic stokers, especially underfeed stokers. The general object of .the invention is to improve the elliciency, durability and convenience of twyer constructions and of furnaces and stokers embodying the same. Particularly, the invention has to do with the improvement of the construction and arrangement of the twyers, giving a novel and effective mode of air' discharge into the fuel bed, with the purpose of promoting the combustion and minimizing the formation of clinkers and .the accumulation of refuse upon the grate and A further-object is to minimize the sifting through the twyers of fine-coal, which has been adecided objection, especially in the types of furnace in which the twyers are I'eciprocated; this objection being eliminated herein by the mode of discharge of air through the air orifices or nozzles. further object is to maintain clear and free of obstruction the air exits or nozzles of the twyers which in prior constructions have had a tendency to clog, thusimpeding the proper flow of air into the and advantages, the present inwentipn .con- 5 sists in the novel features of construction, arrangement, vcombination and detail hereinafter described on illustrated.

Figure 1 is a vertical longitudinal section 'on the line 11 of Fig. 2 showing portions of a furnace and stoker having incorporated the principles of the present inven- 1ine'22 of Fig.1. Fig. 3 is a section similar to Fig.1, showin several successive twyer members on an en arged scale.

Specification of Letters Patent.

.' Application filed August 31, 1918. Serial ll'o. 252,230.

Fig. 4'is a side elevationof one of the twyer members .of-Figs. 1 to 3.

Fig. 5 is a top plan view of one of such twyer members, partly broken away..

Fig. 6 is a transverse section taken on the line 6-6 of Fig. 3;

Fig. 7 in plan view, and r Fig. 8 in section on the line 88 of Fig. 7 show a modified form oftwyer construe tion embodying the present invention.

The front wall 10 and bridge wall 11 of an illustrative type of furnace are shown in F i'g. 1 and the position of a boiler 12 is there. indicated. An underfeed stoker is shown, this for convenience, being indicated of the Well known Riley type and the general'stoke-r features, being largely in accord ance with the Riley stoker, are not made the subject of claim herein. These features are shown for the purpose of disclosing one modeof practising the present invention and will not be fully herein described since the details are otherwise obtainable, for example from the patent of Riley No. 1,322,822,

' of furnace 'or stoker.

' I partially describe the illustrated stoker as follows. I have indicated the usual ex ter'ior coal hopper 13 beneath whichi the infeeding ram 14 driven from a crank 15 so as to reciprocate within a casing 16, the

ram thereby forcing the coal from the hopper inwardly through the throat or entrance 17 of the furnace. As seen in Fig. 2 there are a series of rams and entrances and within the furnace a corresponding series of retorts 18 into which the entering coal passes,

the coal resting on the retort bottom or plate 19. The space beneath the retorts may constitute a Wind box 20 for the supply of air. of combustion to the twyers and' fuel bed. Thin plates 21 are vshown, preventingv the sifting of coal from the retorts into the wind box.

The retorts 18 are constitutedby-the .s ac

ing apart of a series of air boxes 22. ach

of these air boxes comprises side walls 23 and a bottom wall 24 suitably apertured to freely admit air from the wind'boxf It will be. understood that in usual J practice the respective air boxes sustain twyers which in turn sustain portions of the fuel bed and admit forced drafts .of'a'ir thereto. The

construction and arrangement 7 of twyers herein disclosed is a departure from heretofore known constructions.

Fig. 1 shows roughly the line of the fuel bed'25 overlying the retorts and air boxes/ The'rear or lower portion of the bed rests on a dump plate 26 which isintermittently lowered and raised by means of a roller 27. Thisroller can be adjusted rearwardly and forwardly by. a rack and pinion device 28. The forward endof the dump plate 26 is connected by a link 29 with the rear or lower end 30 of the grate. This part of the grate is ,slidingly supported on bearing plates 31 so that the grate can be moved rearward and forward as is frequently done in this type of stoker. When the grate moves rearwardly the dump plate descends and the latter rises when the grate returns forwardly.

'Reciprocated by the connectlons which operate the ram 14 is shown a bar 32, this serving to convey a reciprocation or agitating movement to a stout cylinder or plunger 33. There will be a plurality of such. plungers and they extend inwardly through the furnace front wall and connect with the up- 3 per end of the grate. As the result of this construction, the entire grate reciprocates rearwardly and forwardly substantially-as indicated by the double arrow 34.

Coming now more particularly to the features of the present invention I have shown,

I above and resting upon the side walls 32 of each of the air boxes, a series of twyer members 35. The general arrangement is shown in Figs. 1 and 2, Figs. 3 and 6 show the relative arrangement ofsuccessive twyer members, while Figs. 4 and 5 are exterior views of a single member.

What; may be called the body portion 36 of each twyer member is the main transyerse portion thereof and this at the opposite side edges is shown as having downward flanges 37. Each of these flanges has small air dis charge openings 38 and larger ones 39 for delivering air laterally into the fuel bed within each retort. The downward flange 37 of each twyer member rests directlyrupon the next lower twyer member, the relative position being determined -as will be explained. The entire bank of twyers is sup ported directly'upon the side walls 23 of the air boxes and for this purpose each twyer side plate or flange 37 is extended forwardly at 40, each extension having an inclined foot or flange 41"0f suitable construction and location to rest upon the retort wall 23.

As clearly seen in Figs. 1 and 3 the several twyer members snugly nest together and form a solid united construction with substantially'no openings except the lateral openings 38 and 39 already referred to, and upward openings to 'be described.

The transverse or body portion 36 of each operates with the next lower twyer member H to form an outwardly or upwardly directed air exit extending transversely across. Directly above each nose portion 43 is a slant ing twyer portion 44 substantially parallel with the upper edges of the retort side plates 23. At the top of the incline 44 the contour declines, forming a ridge 45 and a second or downward slant 46, which inturn is succeeded by a depression or valley47, succeeding which is a second ridge 48 and a final downward extension 49.

The upward air nozzle or orifice 50, be-

. fore referred to, is formed between the nose portion 43 of one twyer and the first ridge 45 of the next lower twyer, as indicated. the depression or valley 47 and the second ridge 48 being of valuable service in preventing any coal siftings, which may enter the nozzle 50,- from passing into the air box. The valley gathers the siftings and the force of the draft-eventually carries them upward into the fuelbed.

The relative arrangement and spacing of the successive twyers may be secured by means of the spacing pins 51 extending downwardly beneath the forward edge of each twyer member andcorresponding re- .cesses 52 formed in the valleys 47, into each of which fits the spacing pin of the next twyer member above. 49 may be formed with a notch 53 and in this notch is shown engaged the head of a bolt 54. The several bolts 54 pass downwardly through the air boxes and are secured by nuts beneath the bottom walls 24, so that the entire grate and twyer construction is firmly bound in position. .7

In order to complete the construction of the grateT have shown at the top of the seriesof twyers a twyer'55 of special form.

coiiperating with 'the' twyer beneath and forming a proper terminus for the upper end of the grate. Similarly a'special twyer 56 is shown at the bottom of the series, and in some cases there may advantageously be provided intermediate special twyers 57 between the twyer 56 and the dead plate 58, from which the fuel bed passes on to the dumping grate 26. i e

The modification shown in Figs. 7 and 8 is applicable to astoker wherein one half of each twyer system shifts forwardly while the other half shifts rearwardly giving an eflective agitating movement. Also this modification shows a twyer with rounded nose. The twyer is shown split longitudinally into two opposite parts 35 and 35",

The inner extension eedeca one of which may be moved forwardly while the other is moved i'earwardly. Each half comprises a depression 47 or 47 through which air may-be discharged upwardly between two successive twyers. Each half member has a downwardlyextendingspacing pin 51 or 51 and a recess 52? or 52 tion' and operation, as described, 'the same vances toward the furnace rear. The invenbeing shown applied to a furnace grate of, the type having one or more inclined air boxes, beside and above which the fuel adtion in an' important aspect consists in a twyer construction comprising a 'series of flatwise twyer membersvresting in overlaping relation upon each other above the air ox, each member having a ridge spaced sufficiently from the outer edge of the next higher member to form between them an outwardly and upwardly directed air nozzle. This nozzle, the exit of which is marked 50, Fig. 3,is seen to be a tapering or converging nozzle or passage so that the air passes efiectively to the exit and istherefrom forcibly discharged upwardly into the fuel bed. The space between the portions 47 48 and 49 of-one twyerand the portions 44, 45 and 46 0f the next higher one is. fed freely by air from beneath and this air passes out laterally through openings 38 and 39 into the opposite retorts and longitudinally through the orifice 50, which extends substantially the full width of the twyer, so

that air is effectively fed to all parts of the fuel bed. Therefore, the upward air through the nozzle of the present invention supplements the lateral air which passes into the retorts. The lateral orifices 38 and 39 are graduated so that the deeper ones are the larger and thus air 1s fed'efi'ectively throughout the fuel within theretorts. The shallowest parts of the fuel bed, that is, above the twyer members, are supplemenr tally fed with air by the successive orifices or nozzles 50. Thus all parts of the fuel bed are effectively and theroughlyreached by the air of combustionand this reduces the tendency of linkers and improves the operajtion of the furnace. The arrangement of the successive slanting portions 44 in substantial alinement isfognd inpractice to give an" effective fuel support over which thefuel bed passes without hindrance and without tendency to clog theorifices 50. The orifices substantially do not break the continuity of the supporting surface and .yet maintain their effective airsupplying operation. The valley or depression 47 beneath each twyer edge or nose 43 receives any. fine material terial is unable to sift down into the air box because it is effectively held in the depresthat tends to sift through, but this fine masion until again driven outwardl into the fuel bed by the constant blasts 0 air. The spacing pins or pieces 51 fitting in corresponding recesses maintain the predetermined relation of the parts, and the inwardly extending portions 40' and 41 give proper connection and support of the twyer system upon the inclined air box, the entirety'being held securely by the downward bolts, which engage the interior portions of each twyer member and are thus protected from deterioration.

It will be' noted that the air discharge from the nozzles 50 between successive twyer members is substantially upward, as distinguished from horizontally rearward,

although notnecessarily vertically upward.

This-feature of an upward nozzle, especially in connection with the valley or basin im-' mediately Within the orifice, is of value, as already explained, in preventing sifting of ashes orcoal into the air boxes. This is especially true with furnaces having reciproeating twyers, and heretofore there has been substantial difliculty with coal siftings dropping into the air passages on each reciprocation of the twyers. It is found that applicants arrangement minimizes the entry of. -siftings, and as long as the air flow is continued or-when the twyers do not reciprocate there will be practically no entrance of siftings. Whatever material enters in any case is temporarily held by" the valleys and quickly blown out by the movement of air. Any siftings tending to enterthe air box through the lateral openings 38 will also be caught and held in the depression or basin 47 until again blown into the fuel "beds; 1

It will thus be seen that there has been of design, arrangement and other detail may be variously modified without departing from the principles involved, it is not'intended to limit the invention to such mat ter's except in so far as specified in the appended claims.

-What is claimed is:

the fuel bed. advances descendingly toward 1'. For a furnace grate of the type having. inclined air boxes between and above which wise members resting in overlapping relation upon each other and relatively arranged to afford a series of air nozzles directed upwardly into the fuel bed overlying said members.

2. For a furnace grate of the type having inclined air boxes between and above which the fuel bed advances descendingly toward the furnace rear, a twyer system overlying each air box, and comprising a series of flatwise members, the rear lower edge ofeach member so related to the upperedge of the member beneath as to form between them an upwardly directed transverse air nozzle.

3. For a furnace grate of the-type having inclined air boxes between and above which the fuel bed advances descendingly toward the furnace rear, a twyer systemoverlying each air box, and comprising a series of flatwise members resting in overlapping relation upon each other, their outer surfaces in alinement, affording a substantially continuous inclined supporting surface for the fuel, and successive members relatively arranged to afford a series of air nozzles directed upwardly between the members into the fuel bed overlying said members;

4:- For a furnace grate of the type having inclined air boxes between and above which the fuel bed advances descendingly toward the furnace rear, a twyer system overlying each air box, and comprising a series of flatwise members resting in overlapping relation upon each other and relatively. arranged to afford between each two adjacent members an air nozzle directed upwardly into the fuel bed, and a'valley formed beneath each nozzle adapted to catch 'siftings and from which the same may be blown upwardly into the fuel bed.

5. For a furnace grate of the type having inclined air boxes between and above which the fuel bed advances descendingly toward the furnace rear, a twyer system overlying each air box, and comprising a series of flatwise members, the rear lower edge of each member spaced from the next member beneath, and thelatter formed with a ridge and valley beneath such edge, so shaped that.

a converging upwardly directed nozzle is formed.

6. For a furnace grate of the type having inclined air 'boxesbetween and above which 7 For a furnace grate of the type having one or more inclined air boxes beside and above which the fuel bedadvances toward the furnace rear, a twyer construction comprising a series of longitudinal twyer members arranged in overlapping relation upon each other, each member having avalley ;or depression spaced sufliciently below the extreme edge of the next higher memberv to form between them an upwardly directed air nozzle.

8. 'lwyer construction as in claim 7 and wherein a spacing iece maintains the relations ofthe nozzle orming portions of each two adjacent members.

9. Twyer'construction as in claim 7 and wherein eachtwyer member has side walls extending inwardly'beyond the body of the member to where the beveled inner ends of the walls engage the inclined air box.

10. Twyer construction as in claim 7 and wheiein each twyermember has side walls extending inwardly beyond the body of the member to the air box, and a downwardly extending bolt from the'concealed or inner end of the body serves to secure the member in place. v

11. Twyer construction as in claim 1, and wherein the adjacent parts of each pair of twyer members are so formed thatthe upward air nozzle between them is of convergin character. M

in testimony whereof, I

ture hereto.

, HERMAN SGHM'I'DT.

affix my signa- 

